1. Field of the Invention
The present invention relates to a semiconductor technology, and more particularly, to a variable resistive memory device and a method of fabricating the same.
2. Description of the Related Art
As the demand for portable digital application devices, such as digital cameras, MP3 players, personal digital assistants (PDAs), or mobile phones has increased, the nonvolatile memory market has grown rapidly. High-density flash memory devices having low fabricating costs per bit are widely used as programmable nonvolatile memories. However, since flash memories require a relatively high capacity transistor in order to perform hot carrier injection for programming and a tunneling oxide film that is thick enough to endure a high internal voltage in order to ensure reliable data retention, there is a basic limitation in scaling down flash memories. As flash memories have recently reached their scaling limits, nonvolatile memory devices using a variable resistive material have attracted attention as alternative nonvolatile memories.
Since a variable resistive material has bi-stable resistive states that may be reversely changed by an electrical pulse applied thereto, and thus physical characteristics of the variable resistive material may be used as data, a memory device may operate without a transistor and may be easily scaled.
Regarding the scaling down of the variable resistive memory device, a driving device needs to be miniaturized, power consumption needs to be reduced. Especially, when a variable resistive material is a phase-change material, an interference due to thermal crosstalk between adjacent memory cells needs to be suppressed. In detail, when a phase-change memory device is designed to be equal to or less than 65 nm, particularly, equal to or less than 20 nm, heat generated during programming of a selected memory cell may affect a written state of another memory cell adjacent to the selected memory cell, thereby leading to reliability problems such as data loss or malfunction.